Support for Texture Compression

[ksons]

xml3d.js supports the standard browser image formats as textures. Some platforms support compressed texture formats as an WebGL extensions. Most desktops support e.g. S3TC format.

xml3d.js should:

• Support proper setting of textures delivered in a compressed texture format
• Decode compressed textures if used in a Xflow dataflow that requires to access pixel data
• Encode supported texture formats in the HTTP request thus the server can send textures in the best available representation

Library that could be used:
https://github.com/toji/webgl-texture-utils

[jonnenauha]

The library looks good. Seems to have some code for crunch too which would be a nice extra feature :) This is binary parsing so its gonna be quite fast but with a large amount of mipmaps it might still last a while. I would utilize WebWorkers here by default, so that might be good to implement first to the loader interface.